Merge tag 'for-linus-4.21-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:
 "Xen features and fixes:

   - a series to enable KVM guests to be booted by qemu via the Xen PVH
     boot entry for speeding up KVM guest tests

   - a series for a common driver to be used by Xen PV frontends (right
     now drm and sound)

   - two other fixes in Xen related code"

* tag 'for-linus-4.21-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  ALSA: xen-front: Use Xen common shared buffer implementation
  drm/xen-front: Use Xen common shared buffer implementation
  xen: Introduce shared buffer helpers for page directory...
  xen/pciback: Check dev_data before using it
  kprobes/x86/xen: blacklist non-attachable xen interrupt functions
  KVM: x86: Allow Qemu/KVM to use PVH entry point
  xen/pvh: Add memory map pointer to hvm_start_info struct
  xen/pvh: Move Xen code for getting mem map via hcall out of common file
  xen/pvh: Move Xen specific PVH VM initialization out of common file
  xen/pvh: Create a new file for Xen specific PVH code
  xen/pvh: Move PVH entry code out of Xen specific tree
  xen/pvh: Split CONFIG_XEN_PVH into CONFIG_PVH and CONFIG_XEN_PVH

10 files changed, 172 insertions, 79 deletions

diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild
index 0038a2d10a7a..c625f57472f7 100644
--- a/arch/x86/Kbuild
+++ b/arch/x86/Kbuild
@@ -7,6 +7,8 @@ obj-$(CONFIG_KVM) += kvm/
 # Xen paravirtualization support
 obj-$(CONFIG_XEN) += xen/
 
+obj-$(CONFIG_PVH) += platform/pvh/
+
 # Hyper-V paravirtualization support
 obj-$(subst m,y,$(CONFIG_HYPERV)) += hyperv/
 
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8689e794a43c..c2a22a74abee 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -796,6 +796,12 @@ config KVM_GUEST
 	  underlying device model, the host provides the guest with
 	  timing infrastructure such as time of day, and system time
 
+config PVH
+	bool "Support for running PVH guests"
+	---help---
+	  This option enables the PVH entry point for guest virtual machines
+	  as specified in the x86/HVM direct boot ABI.
+
 config KVM_DEBUG_FS
 	bool "Enable debug information for KVM Guests in debugfs"
 	depends on KVM_GUEST && DEBUG_FS
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 747c758f67b7..d1dbe8e4eb82 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -386,7 +386,7 @@ NEXT_PAGE(early_dynamic_pgts)
 
 	.data
 
-#if defined(CONFIG_XEN_PV) || defined(CONFIG_XEN_PVH)
+#if defined(CONFIG_XEN_PV) || defined(CONFIG_PVH)
 NEXT_PGD_PAGE(init_top_pgt)
 	.quad   level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC
 	.org    init_top_pgt + L4_PAGE_OFFSET*8, 0
diff --git a/arch/x86/platform/pvh/Makefile b/arch/x86/platform/pvh/Makefile
new file mode 100644
index 000000000000..5dec5067c9fb
--- /dev/null
+++ b/arch/x86/platform/pvh/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+OBJECT_FILES_NON_STANDARD_head.o := y
+
+obj-$(CONFIG_PVH) += enlighten.o
+obj-$(CONFIG_PVH) += head.o
diff --git a/arch/x86/platform/pvh/enlighten.c b/arch/x86/platform/pvh/enlighten.c
new file mode 100644
index 000000000000..62f5c7045944
--- /dev/null
+++ b/arch/x86/platform/pvh/enlighten.c
@@ -0,0 +1,137 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/acpi.h>
+
+#include <xen/hvc-console.h>
+
+#include <asm/io_apic.h>
+#include <asm/hypervisor.h>
+#include <asm/e820/api.h>
+#include <asm/x86_init.h>
+
+#include <asm/xen/interface.h>
+
+#include <xen/xen.h>
+#include <xen/interface/hvm/start_info.h>
+
+/*
+ * PVH variables.
+ *
+ * pvh_bootparams and pvh_start_info need to live in the data segment since
+ * they are used after startup_{32|64}, which clear .bss, are invoked.
+ */
+struct boot_params pvh_bootparams __attribute__((section(".data")));
+struct hvm_start_info pvh_start_info __attribute__((section(".data")));
+
+unsigned int pvh_start_info_sz = sizeof(pvh_start_info);
+
+static u64 pvh_get_root_pointer(void)
+{
+	return pvh_start_info.rsdp_paddr;
+}
+
+/*
+ * Xen guests are able to obtain the memory map from the hypervisor via the
+ * HYPERVISOR_memory_op hypercall.
+ * If we are trying to boot a Xen PVH guest, it is expected that the kernel
+ * will have been configured to provide an override for this routine to do
+ * just that.
+ */
+void __init __weak mem_map_via_hcall(struct boot_params *ptr __maybe_unused)
+{
+	xen_raw_printk("Error: Could not find memory map\n");
+	BUG();
+}
+
+static void __init init_pvh_bootparams(bool xen_guest)
+{
+	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
+
+	if ((pvh_start_info.version > 0) && (pvh_start_info.memmap_entries)) {
+		struct hvm_memmap_table_entry *ep;
+		int i;
+
+		ep = __va(pvh_start_info.memmap_paddr);
+		pvh_bootparams.e820_entries = pvh_start_info.memmap_entries;
+
+		for (i = 0; i < pvh_bootparams.e820_entries ; i++, ep++) {
+			pvh_bootparams.e820_table[i].addr = ep->addr;
+			pvh_bootparams.e820_table[i].size = ep->size;
+			pvh_bootparams.e820_table[i].type = ep->type;
+		}
+	} else if (xen_guest) {
+		mem_map_via_hcall(&pvh_bootparams);
+	} else {
+		/* Non-xen guests are not supported by version 0 */
+		BUG();
+	}
+
+	if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
+		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
+			ISA_START_ADDRESS;
+		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size =
+			ISA_END_ADDRESS - ISA_START_ADDRESS;
+		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type =
+			E820_TYPE_RESERVED;
+		pvh_bootparams.e820_entries++;
+	} else
+		xen_raw_printk("Warning: Can fit ISA range into e820\n");
+
+	pvh_bootparams.hdr.cmd_line_ptr =
+		pvh_start_info.cmdline_paddr;
+
+	/* The first module is always ramdisk. */
+	if (pvh_start_info.nr_modules) {
+		struct hvm_modlist_entry *modaddr =
+			__va(pvh_start_info.modlist_paddr);
+		pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
+		pvh_bootparams.hdr.ramdisk_size = modaddr->size;
+	}
+
+	/*
+	 * See Documentation/x86/boot.txt.
+	 *
+	 * Version 2.12 supports Xen entry point but we will use default x86/PC
+	 * environment (i.e. hardware_subarch 0).
+	 */
+	pvh_bootparams.hdr.version = (2 << 8) | 12;
+	pvh_bootparams.hdr.type_of_loader = ((xen_guest ? 0x9 : 0xb) << 4) | 0;
+
+	x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
+}
+
+/*
+ * If we are trying to boot a Xen PVH guest, it is expected that the kernel
+ * will have been configured to provide the required override for this routine.
+ */
+void __init __weak xen_pvh_init(void)
+{
+	xen_raw_printk("Error: Missing xen PVH initialization\n");
+	BUG();
+}
+
+static void hypervisor_specific_init(bool xen_guest)
+{
+	if (xen_guest)
+		xen_pvh_init();
+}
+
+/*
+ * This routine (and those that it might call) should not use
+ * anything that lives in .bss since that segment will be cleared later.
+ */
+void __init xen_prepare_pvh(void)
+{
+
+	u32 msr = xen_cpuid_base();
+	bool xen_guest = !!msr;
+
+	if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
+		xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
+				pvh_start_info.magic);
+		BUG();
+	}
+
+	hypervisor_specific_init(xen_guest);
+
+	init_pvh_bootparams(xen_guest);
+}
diff --git a/arch/x86/xen/xen-pvh.S b/arch/x86/platform/pvh/head.S
index 1f8825bbaffb..1f8825bbaffb 100644
--- a/arch/x86/xen/xen-pvh.S
+++ b/arch/x86/platform/pvh/head.S
diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 1ef391aa184d..e07abefd3d26 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -74,6 +74,7 @@ config XEN_DEBUG_FS
 	  Enabling this option may incur a significant performance overhead.
 
 config XEN_PVH
-	bool "Support for running as a PVH guest"
+	bool "Support for running as a Xen PVH guest"
 	depends on XEN && XEN_PVHVM && ACPI
+	select PVH
 	def_bool n
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index dd2550d33b38..084de77a109e 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
 OBJECT_FILES_NON_STANDARD_xen-asm_$(BITS).o := y
-OBJECT_FILES_NON_STANDARD_xen-pvh.o := y
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities
@@ -38,7 +37,6 @@ obj-$(CONFIG_XEN_PV)		+= xen-asm.o
 obj-$(CONFIG_XEN_PV)		+= xen-asm_$(BITS).o
 
 obj-$(CONFIG_XEN_PVH)		+= enlighten_pvh.o
-obj-$(CONFIG_XEN_PVH)	 	+= xen-pvh.o
 
 obj-$(CONFIG_EVENT_TRACING)	+= trace.o
 
diff --git a/arch/x86/xen/enlighten_pvh.c b/arch/x86/xen/enlighten_pvh.c
index 02e3ab7ff242..35b7599d2d0b 100644
--- a/arch/x86/xen/enlighten_pvh.c
+++ b/arch/x86/xen/enlighten_pvh.c
@@ -6,103 +6,45 @@
 #include <asm/io_apic.h>
 #include <asm/hypervisor.h>
 #include <asm/e820/api.h>
-#include <asm/x86_init.h>
 
+#include <xen/xen.h>
 #include <asm/xen/interface.h>
 #include <asm/xen/hypercall.h>
 
-#include <xen/xen.h>
 #include <xen/interface/memory.h>
-#include <xen/interface/hvm/start_info.h>
 
 /*
  * PVH variables.
  *
- * xen_pvh pvh_bootparams and pvh_start_info need to live in data segment
- * since they are used after startup_{32|64}, which clear .bss, are invoked.
+ * The variable xen_pvh needs to live in the data segment since it is used
+ * after startup_{32|64} is invoked, which will clear the .bss segment.
  */
 bool xen_pvh __attribute__((section(".data"))) = 0;
-struct boot_params pvh_bootparams __attribute__((section(".data")));
-struct hvm_start_info pvh_start_info __attribute__((section(".data")));
-
-unsigned int pvh_start_info_sz = sizeof(pvh_start_info);
 
-static u64 pvh_get_root_pointer(void)
+void __init xen_pvh_init(void)
 {
-	return pvh_start_info.rsdp_paddr;
+	u32 msr;
+	u64 pfn;
+
+	xen_pvh = 1;
+	xen_start_flags = pvh_start_info.flags;
+
+	msr = cpuid_ebx(xen_cpuid_base() + 2);
+	pfn = __pa(hypercall_page);
+	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
 }
 
-static void __init init_pvh_bootparams(void)
+void __init mem_map_via_hcall(struct boot_params *boot_params_p)
 {
 	struct xen_memory_map memmap;
 	int rc;
 
-	memset(&pvh_bootparams, 0, sizeof(pvh_bootparams));
-
-	memmap.nr_entries = ARRAY_SIZE(pvh_bootparams.e820_table);
-	set_xen_guest_handle(memmap.buffer, pvh_bootparams.e820_table);
+	memmap.nr_entries = ARRAY_SIZE(boot_params_p->e820_table);
+	set_xen_guest_handle(memmap.buffer, boot_params_p->e820_table);
 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
 	if (rc) {
 		xen_raw_printk("XENMEM_memory_map failed (%d)\n", rc);
 		BUG();
 	}
-	pvh_bootparams.e820_entries = memmap.nr_entries;
-
-	if (pvh_bootparams.e820_entries < E820_MAX_ENTRIES_ZEROPAGE - 1) {
-		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].addr =
-			ISA_START_ADDRESS;
-		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].size =
-			ISA_END_ADDRESS - ISA_START_ADDRESS;
-		pvh_bootparams.e820_table[pvh_bootparams.e820_entries].type =
-			E820_TYPE_RESERVED;
-		pvh_bootparams.e820_entries++;
-	} else
-		xen_raw_printk("Warning: Can fit ISA range into e820\n");
-
-	pvh_bootparams.hdr.cmd_line_ptr =
-		pvh_start_info.cmdline_paddr;
-
-	/* The first module is always ramdisk. */
-	if (pvh_start_info.nr_modules) {
-		struct hvm_modlist_entry *modaddr =
-			__va(pvh_start_info.modlist_paddr);
-		pvh_bootparams.hdr.ramdisk_image = modaddr->paddr;
-		pvh_bootparams.hdr.ramdisk_size = modaddr->size;
-	}
-
-	/*
-	 * See Documentation/x86/boot.txt.
-	 *
-	 * Version 2.12 supports Xen entry point but we will use default x86/PC
-	 * environment (i.e. hardware_subarch 0).
-	 */
-	pvh_bootparams.hdr.version = (2 << 8) | 12;
-	pvh_bootparams.hdr.type_of_loader = (9 << 4) | 0; /* Xen loader */
-
-	x86_init.acpi.get_root_pointer = pvh_get_root_pointer;
-}
-
-/*
- * This routine (and those that it might call) should not use
- * anything that lives in .bss since that segment will be cleared later.
- */
-void __init xen_prepare_pvh(void)
-{
-	u32 msr;
-	u64 pfn;
-
-	if (pvh_start_info.magic != XEN_HVM_START_MAGIC_VALUE) {
-		xen_raw_printk("Error: Unexpected magic value (0x%08x)\n",
-				pvh_start_info.magic);
-		BUG();
-	}
-
-	xen_pvh = 1;
-	xen_start_flags = pvh_start_info.flags;
-
-	msr = cpuid_ebx(xen_cpuid_base() + 2);
-	pfn = __pa(hypercall_page);
-	wrmsr_safe(msr, (u32)pfn, (u32)(pfn >> 32));
-
-	init_pvh_bootparams();
+	boot_params_p->e820_entries = memmap.nr_entries;
 }
diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
index bb1c2da0381d..1e9ef0ba30a5 100644
--- a/arch/x86/xen/xen-asm_64.S
+++ b/arch/x86/xen/xen-asm_64.S
@@ -12,6 +12,7 @@
 #include <asm/segment.h>
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
+#include <asm/asm.h>
 
 #include <xen/interface/xen.h>
 
@@ -24,6 +25,7 @@ ENTRY(xen_\name)
 	pop %r11
 	jmp  \name
 END(xen_\name)
+_ASM_NOKPROBE(xen_\name)
 .endm
 
 xen_pv_trap divide_error